Chondrogenic Potential of Articular Chondrocytes Depends on Their Original Location

Abstract

Objective: This study aimed to investigate the regenerative capacity of chondrocytes derived from debrided defect cartilage and healthy cartilage from different regions in the joint to determine the best cell source for regenerative cartilage therapies. Methods: Articular cartilage was obtained from Outerbridge grade III and IV cartilage lesions and from macroscopically healthy weight-bearing and nonweight-bearing (NWB) locations in the knee. Chondrocytes isolated from all locations were either pelleted directly (P0 pellets) or after expansion (P2 pellets) and analyzed for glycosaminoglycan (GAG), DNA, and cartilage-specific gene expression. Harvested cartilage samples and cultured pellets were also analyzed by Safranin O histology and immunohistochemistry for collagen I, II, and X. Immunohistochemical stainings were quantified using a computerized pixel-intensity staining segmentation method. Results: After 4 weeks of culture, the P0 pellets derived from grade III or healthy weight-bearing chondrocytes contained more ( p < 0.015) GAG and GAG normalized per DNA compared to those from grade IV and NWB locations. After expansion, these differences were lost. Cartilage-specific gene expression was higher ( p < 0.04) in P0 pellets from grade III chondrocytes compared to grade IV chondrocytes. Semiquantitative immunohistochemistry showed a more intense ( p < 0.033) collagen I and X staining for grade IV debrided cartilage compared to grade III and weight-bearing cartilage. Also, collagen type X staining intensity was higher ( p < 0.033) in NWB cartilage compared to grade III and weight-bearing regions. Conclusion: Chondrocytes derived from debrided cartilage perform better than cells from the NWB biopsy site, however, this difference is lost upon expansion. Based thereon, the debrided defect cartilage could be a viable donor site for regenerative cartilage surgery.

Chondrocyte-based intraoperative processing strategies for the biological augmentation of a polyurethane meniscus replacement

“…Improved cell yields were observed for articular cartilage with a cell yield of 2-2.5 x 10 6 cells/g from a clinically relevant biopsy (~300 mg) (17) using a reduced isolation time of 30 min. This is comparable to previous work by Bekkers et al who report similar cell yields 0.56-1.06 x 10 6 cells/g (26). Exposure time was found to be more detrimental to cell viability than concentration as previously demonstrated by Bos et al (46).…”

“…In this manner, the application of fresh chondrocyte based biologics demonstrates the Where the use of enzymatic isolation protocols intraoperatively is largely reliant on the evolving regulatory landscapes, the efficacy of tissue transplantation with minced cartilage without the need for enzymatic cell isolation has been demonstrated in cartilage approaches (26,29). However, to the best of the authors' knowledge, the application of such has not been applied to meniscal replacement procedures.…”

“…Similarly, the success of such protocols has previously been demonstrated for cartilage regeneration (26). These protocols could potentially be adopted to yield an intraoperative strategy for articular cartilage processing and application to improve integration of a meniscal replacement.…”

Interleukin-6 is elevated in synovial fluid of patients with focal cartilage defects and stimulates cartilage matrix production in an in vitro regeneration model

“…The use of post-mortem collection of healthy synovial fluid and cells as opposed to the intra-operative collection of OA and cartilage defect synovial fluid and cells is less likely to have affected the results. Previous work from our group showed that there was no difference in viability between freshly isolated chondrocytes from healthy (post-mortem obtained) and grade III cartilage defect tissue [49], which is in line with the observation that viability and cartilage matrix content is very much unaltered within the first 24 hours [74-76]. Synovial fluid is contained in a relatively isolated compartment [77,78] and when kept at 4°C, levels of IL-6 have been shown to be stable for more than six hours [79].…”

“…The debrided cartilage was used for chondrocyte isolation. Chondrocytes from this location were recently shown to have good regenerative capacities compared to cells harvested from non-weight bearing cartilage normally used for ACI [49]. Of the 22 patients with symptomatic cartilage defects, one had an associated ACL injury and a history of partial menisectomy, another three had previously received partial menisectomies and one had undergone an ACL reconstruction.…”